Drafting instrument.



No. 759,566. PATENTED MAY 10, 1904.

R. P. STOUT.

DRAFTING INSTRUMENT.

APPLICATION FILED DBO. 26, 1902.

N0 MODEL. 2 SHEETS-BHEET 1.

No. 759,566. PATENTED MAY 10, 1904. R. P. STOUT.

DRAFTING INSTRUMENT.

APPLICATION FILED DBO. 26, 1902. N0 MODEL. 2 sums-45mm 2.

UNITED STATES Patented May 10, 1904.

PATENT OFFICE.

ROBERT PAUL STOUT, OF BETHLEHEM, PENNSYLVANIA.

DRAFTING INS TRUMENT.

SIEGIFICATION forming part of Letters Patent No. 759,566, dated May 10, 1904.

Application filed December 26, 1902. Sena-1N0. 136,588. (No model.)

To all whom it may concern.-

Be it known that I, Bonner PAUL STOUT, of Bethlehem, in the county of N orthampton,and in the State of Pennsylvania, have invented a certain new and useful Improvement in Drafting Instruments; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being bad to the accompanying drawings, in which,-

Figure 1 is a plan view of a drafting instrument embodying my invention, the instru- I view on the line .2 2 of Fig. 3.

meet being shown as set to draw a curved line that is concave to the instrument. Fig. 2 is a like view of such instrument set to draw a line that is convex to the instrument. Fig. 3 is a vertical sectional view taken on the line m :1; of Fig. 2. Fig. 4: is an enlarged sectional Fig. 5 is a detail plan view of the center slide and block. Fig. 6 is an end view of Fig. 5. Fig. 7 ,is a cross-section on the line 4 1 of Fig. 5, and Fig. 8 is a detail sectional view showing the ball-bearing pivots.

Letters of like name and kind. refer to like parts in each of. the figures.

The object of my invention has been to produce an instrument by which straight lines 7 and curved lines that are either convex or concave toward the instrument can be drawn from a single position of the instrument, such curved lines having, if desired, any radii from those of an ordinary beam-compass to infinity; and to such ends my invention consists in the drafting instrument herein specified.

In carrying my invention into practice I provide a base A, on which is formed a guideway consisting of a pair of overhanging ribs or guides. main slide B is mounted in the -gu1de\vay of the base and 1S movablealong and adjustable in such guideway by means of a hand-scrcw C, that is journaled in a cap 0,

secured across the outer end of the guideway ing-surfaces Z) and 7) of the main slide B, which side bars are connected by a head a" of such sizeand shape as to lit between and under the said ribs. A similar head is formed on the opposite ends of the side bars (Z, and a tapering or flaring recess (Z is formed in such head, the head being thereby divided into two sections d and (2*, respectively. Upon the opposing walls of the recess the ribs (Z are formed, and a wedge E is mounted in such rccess and is provided with grooves to receive the said ribs whereby the said wedge is guided. A hand-screw F is journaled in the head d and is threaded into the wedge, and by means of such screw the wedge is moved. Movement of the wedge causes the sections (Z and (1* to be spread apart and to bind against the guides of the main slide B, thus clamping the block-slide therein.

The side bars (Z of the block-slide form between them a guideway, in which is mounted the block H, the latter being movable along such guideway by means of a hand-screw I, that is journaled in the block-slide and that is threaded into the block.

A frame K, consisting, preferably, of four links of equal length pivoted together at their ends and forming a parallelogram, is con nected to a pivot L on the main slide by a pair of links M, which are mounted at one end of said pivot L and at the other end are pivoted on opposite pivots N of the said frame. .A single link 0, that is mounted on a pivot P on the block H, is connected to the frame K by being mounted on a pivot Q of such frame, that is between the pivots N. The pivot P is received by the link 0 either in a hole R at the end of such link or in a hole S intermediate the ends thercof. The pivots N are, as illustrated in Fig. 8, formed with ahead Z, such head having a seat Z formed in its lower face to receive a ball T. The ball is held in placein its seat by a sleeve U, that fits around the head, incloses the ball, and which is contracted at its lower end to prevent the escape of the ball. This construction provides a convenient support for the frame and at the same time permits a free movement thereof over the drawing-table. The pivot V of the frame K, which pivot is farthest from the centers L and P, is provided with a hole in which a pencil or pen is mounted in any desired manner. Scales W and X are provided on opposite sides of the main slide, and corresponding marks 20 and w are respectively formed on opposite sides of the block for positioning the block with respect to the main slide. The scale W is for use when the pivot P engages the hole R in the link 0, and the scale X is for use when the said pivot engages the hole S of such link.

The law of the above-described instrument is that if the distance between the pivots P and Q or the effective length of the link 0 is equal to that between the pivot P on the block H and the pivot L on the main slide the line described by the pen or pencil will be straight. If the distance between the pivots P and Q of the link 0 is greater than the distance between the pivots P and L, the line described by the instrument will be concave to the instrument, and if the distance between the pivots P and Q is less than that between the pivots P and L the line described by the instrument will be convex toward the instrument.

In the operation of my drafting instrument, as above illustrated, the base is set on the drawing-board, preferably in a position perpendicular to the line to be drawn, and in the case of a straight line it must be actually in a position perpendicular to such line. To draw a curve concave toward the instrument, the block-slide D is shifted by hand in its guideway to approximately set the mark 20 on block H opposite the proper mark on the scale W to produce a curve of the desired radius. The block-slide is then clamped in position by means of the wedgeE. The block H is then shifted in its slide by means of the screw G until the mark 20 thereon accurately registers with the desired mark on the scale WV, this being readily accomplished because of the fine thread on the said screw. The main slide, together with the whole linkage, is then, Without affecting the adjustment in ,any manner, moved toward the point through which the line is to pass, such movement being effected by means of the screw 0. Since it is necessary to make the distance between the pivots P and L greater than that between the pivots P and Q, in order to draw a curve convex to the instrument and since it would make the base inconveniently long to provide for all the movement of the block necessary to draw such curves when of comparatively short radius, in drawing such curves I prefer for such curves to put the pivot Q in the hole S intermediate the ends of the link, and when this is done the scale X is used, the operation being substantially the same as with that before described.

It is obvious that various changes in the above-illustrated construction can be made which will be within the scope of my invention.

The base or any of the slides or blocks thereon constitute supports for the fixed pivots upon which the linkage swings. Manifestly any other fixed part could be used to perform the function of and as the equivalent of the parts mentioned.

By the term support in the claims is meant the main slide B, whether or not mounted upon the base A or other form of base.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a drafting instrument, the combination of a frame consisting of four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot and at their opposite ends to opposite pivots of the said frame, a link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, said single link being so constructedas to permit varying the distance between said fixed pivots.

2. In a drafting instrument, the combination of a frame consisting of four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot, and pivoted at their opposite ends to opposite pivotsof said frame, a link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, said single link being so constructed that its operative length may be varied.

3. In a drafting instrument, the combination of a frame consisting of four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot, and pivoted at their opposite ends to opposite pivots of said frame, a link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, said pair of links and said single link being so constructed that their operative lengths may be varied. v

4. In a drafting instrument, the combination of a frame consisting of four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot, and pivoted at their opposite ends to opposite pivots of said frame, a link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, a support for one of said fixed pivots, and a block guided upon said support,

said block supporting the other of said fixed pivots.

5. In a drafting instrument, the combinatio of a frame consisting of four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot, and pivoted at their opposite ends to opposite pivots of said frame, a link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, a support for one of said fixed pivots, a block guided upon said support, said block supporting the other of said fixed pivots, and a scale on said support for positioning said block.

6. In a drafting instrument, the combination TOO of a frame consisting of four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot, and pivoted at their opposite ends to opposite pivots of said frame, a link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, a support for one of said fixed pivots, a block guided upon said support, said block supporting the other of said fixed pivots, and a screw mechanism for adjusting said block.

7. In a drafting instrument, the combination of a frame consisting of four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot and at their opposite ends to opposite pivots of said frame, a link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, means for varying the distance between said fixed pivots, a base, and a slide mounted on said base, said before-mentioned parts except said base being mounted on said slide.

8. In a drafting instrument, the combination of a frame consisting of four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot, and pivoted at their opposite ends to opposite pivotsof said frame, a link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, a support for one of said fixed pivots, said support having a guideway, a block-slide supporting the other of said fixed pivots, and mounted in said guideway, said block-slide being formed with two parts having a flaring opening between the same, a wedge mounted in said 'flaring opening and means for moving said wedge to clamp said block-slide in its guideway.

9. In a drafting instrument, the combination of a frame consisting of four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot, and pivoted at their 0pposite ends to opposite pivots of said frame, a

link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, a support for one of said pivots, said support having a guideway, a block-slide mounted in said guideway, means for clamping said block-slide in its guideway, a block guided on said block-slide, and supporting the other of said fixed pivots, and means for shifting said block in its block-slide.

10. In a drafting instrument, the combination of aframe consistingof four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot, and pivoted at their opposite ends to opposite pivots of said frame, a link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, said link being so constructed that its operative length may be varied, a support for one of said fixed pivots, a block guided upon said support, said block supporting the other of said fixed pivots, and a scale on said support for positioning said block.

11. In a drafting instrument, the combination of a frame consisting of four links pivoted together, a pair of links pivoted at one end to a normally fixed pivot, and pivoted at their opposite ends to opposite pivots of said frame,

a link pivoted to one of the pivots of said frame between said opposite pivots and to a normally fixed pivot, said link havinga plurality of holes for receiving its pivots, a support for one of said fixed pivots,a block guided upon said support, said block supporting the other of said fixed pivots, and a plurality of scales on said support for positioning said block according to the holes occupied by the pivot of said link having a plurality of holes therefor. In testimony that 1 claim the foregoing I have hereunto set my hand.

R. PAUL STOUT. Witnesses:

FREDERICK G. Hue-urns, J 01m Ros EWARNE, Jr. 

